Question

假设我有一个包含3个表的数据库：

玩家（PK id_player，名字......），
锦标赛（PK id_tournament，名字......），
游戏（PK id_turn，FK id_tournament，FK id_player和得分）

玩家参加锦标赛。名为Game的表记录每个玩家在不同比赛中的得分）

我想创建一个如下所示的视图：

    torunament_name     Winner     highest_score
    Tournament_1        Jones                300
    Tournament_2        White                250

我尝试了不同的aproaches，但我对sql相当新（并且alsoto这个论坛）我尝试使用union all子句，如：

    select * from (select "Id_player", avg("score") as "Score" from 
    "Game" where "Id_tournament" = '1' group by "Id_player" order by 
    "Score" desc) where rownum <= 1 
    union all
    select * from (select "Id_player", avg("score") as "Score" from 
    "Game" where "Id_tournament" = '2' group by "Id_player" order by 
    "Score" desc) where rownum <= 1;

和ofc它有效，但每当锦标赛发生时，我都必须手动添加一个选择语句，并使用Id_torunament = nextvalue

编辑：因此，让我们说id为1的玩家在锦标赛中获得50分，玩家2获得40分，玩家1获胜，因此该表应该只显示玩家1作为获胜者（或者如果其可能的2或更多玩家，如果它的平局）这场比赛。下一行显示第二场比赛的获胜者。我不认为我会在同一场比赛中为一名球员投入多场比赛，但如果我愿意的话，可能会从他的所有得分中算出平均值。

EDIT2：创建表脚本：

    create table players 
    (id_player numeric(5) constraint pk_id_player primary key, name 
    varchar2(50));
    create table tournaments 
    (id_tournament numeric(5) constraint pk_id_tournament primary key, 
    name varchar2(50));
    create table game 
    (id_game numeric(5) constraint pk_game primary key, id_player 
    numeric(5) constraint fk_id_player references players(id_player), 
    id_tournament numeric(5) constraint fk_id_tournament references 
    tournaments(id_tournament), score numeric(3));

RDBM screenshot

最终编辑：好的，如果有人想知道我使用的是Jorge Campos脚本，请稍微更改一下它就可以了。谢谢大家的帮助。不幸的是我还不能提出意见，所以我只能通过发帖来表示感谢。下面是最后的剧本：

select
   t.name, 
   p.name as winner, 
   g.score
from
   game g inner join tournaments t
           on g.id_tournament = t.id_tournament
          inner join players p
           on g.id_player = p.id_player
          inner join 
              (select g.id_tournament, g.id_player,
                      row_number() over (partition by t.name order by 
    score desc) as rd from game g join tournaments t on 
    g.id_tournament = t.id_tournament
          ) a
       on g.id_player = a.id_player
          and g.id_tournament = a.id_tournament
          and a.rd=1
order by t.name, g.score desc;

Answer 1

假设你想要什么＆＃34;在每场比赛中显示每个球员的高分＆＃34; 您的查询将如下所示在MS Sql server

中

select 
        t.name as tournament_name,
        p.name as Winner,
        Max(g.score) as [Highest_Score]
from Tournmanents t
Inner join Game g on t.id_tournament=g.id_tournament
inner join Players p on p.id_player=g.id_player
group by 
g.id_tournament,
g.id_player,
t.name,
p.name

Answer 2

根据您使用的RDBM，可以简化此查询。

select
   t.name, 
   p.name as winner, 
   g.score
from
   game g inner join tournaments t
           on g.id_tournament = t.id_tournament
          inner join players p
           on g.id_player = p.id_player
          inner join 
              (select id_tournament, 
                      id_player,
                      row_number() over (partition by t.name order by score desc) as rd
                 from game
              ) a
           on g.id_player = a.id_player
              and g.id_tournament = a.id_tournament
              and a.rd=1
order by t.name, g.score desc

Answer 3

请检查这是否适用于您

SELECT  tournemntData.id_tournament ,
        tournemntData.name ,
        dbo.Players.name ,
        tournemntData.Score
FROM    dbo.Game
        INNER JOIN ( SELECT dbo.Tournaments.id_tournament ,
                            dbo.Tournaments.name ,
                            MAX(dbo.Game.score) AS Score
                     FROM   dbo.Game
                            INNER JOIN dbo.Tournaments ONTournaments.id_tournament = Game.id_tournament
                            INNER JOIN dbo.Players ON Players.id_player = Game.id_player
                     GROUP BY dbo.Tournaments.id_tournament ,
                            dbo.Tournaments.name
                   ) tournemntData ON tournemntData.id_tournament =Game.id_tournament 

INNER JOIN dbo.Players ON Players.id_player = Game.id_player
WHERE tournemntData.Score = dbo.Game.score

SQL - 为不同类别选择最高分数

3 个答案: